The AVR32 Registers view displays all registers and bit fields for the part used in the active project, or for the part belonging to the current debug session.
The text field is used for entering search constraints. You can enter a path to a register or bit field starting with a /. Starting with /pio will display all registers which name starts with that value. Continuing with /pioc/odsr will display only that register. If you instead enter just odsr all of the registers with that name will be displayed, regardless of the which module they belong to. Pressing tab in this field moves focus to the tree view and Enter will expand all nodes in the tree.
Note that AVR32 Studio will remember the last constraints used and these are available in the combo list. Simply pick a value from the list in order to apply the constraints.
When inside the tree view one can double click or press space on a node in order to add it to the watched registers list. This will enabling tracking of the register value while debugging. A watched register will have it's value(s) updated whenever the MCU is suspended. It is also possible to change this value. The value editor is enabled when you double click on the value or press enter when the row is selected. Note that you must be debugging and the MCU must be in suspended state.